Berkson et al. found that self-injurious behavior (SIB) emerges early in life and occurs relatively frequently in birth-to-three years old children with disabilities. In the investigators' two-year study of SIB in birth-to-three years old children with disabilities, ten out of 15 children have exhibited SIB or proto-SIB (e.g., head hit without tissue damage) for nonsocial reasons. The children exhibited lower levels of SIB and proto-SIB during high-stimulation conditions and higher levels during low-stimulation conditions, suggesting that these behaviors serve a self-stimulatory function. This finding is surprising because a substantial proportion of older individuals with developmental disabilities exhibit SIB that is sensitive to social consequences, such as gaining preferred items and caregiver attention, or escaping nonpreferred situations. The proposed study will assess an early intervention package designed to (a) decrease current nonsocial SIB and proto-SIB via response blocking coupled with teaching the participants how to play with toys that provide sensations similar to those produced by SIB or proto-SIB; and (b) increase the participants' ability to appropriately request social consequences via parent responsiveness training and early communication training so they do not learn to control social consequences by engaging in SIB. The study will evaluate the effects of this early intervention package for SIB via a series of multiple baselines. Individual interrupted time series analyses will evaluate changes in dependent variables from baseline to intervention phases. If, as is expected, results show decreased SIB and proto-SIB and increased appropriate communication for social consequences, it will stand as a successful pilot study for a large randomized investigation of whether this early intervention package can prevent the development of chronic SIB in children with moderate to profound disabilities.